1. Field of the Invention
This invention relates to solar heating systems and, more particularly, to improved control systems for such heating systems.
2. Prior Art
In the past, particularly in connection with solar hot water heating systems, it has been the practice to switch on and off, in response to signals from temperature-differential thermostats, the pump which circulates the solar-heated fluid. Circulation is stopped when the temperature of the circulating fluid falls below the temperature of the already stored, heated water or other fluid. Such a system is subject to "hunting" when the temperature of the stored water and that of the circulating water approach each other.
Such "hunting" or random on-off cycling of the circulation pump is caused by such phenomena as water temperature stratification or by improper sensor location. The results are wasted energy, both electrical and thermal. Unnecessary pump, switch and relay wear also occur.
Therefore, it is an object of my invention to overcome the general disadvantages of prior art control systems in solar heating systems.
It is a further object of my invention to provide a control system which is matched in its thermal characteristics to the thermal characteristics of the solar energy collection system it is controlling.
It is an additional object of my invention to provide a control system for solar heating systems in which automatic compensation is made for ambient temperature variations.